What visibility conditions might require you to use navigation lights at all times?

Using navigation lights at all times is essential in overcast weather and during night-time due to the reduced visibility conditions in these scenarios. When the sun is not shining brightly or is obscured by clouds, visibility can be significantly diminished, making it difficult for other boaters to see you. Similarly, nighttime poses a challenge as darkness greatly impacts visibility, requiring the use of navigation lights to ensure that other vessels can detect your presence and position on the water.

In contrast, clear daylight typically provides sufficient visibility, often negating the immediate need for navigation lights. Strong winds alone do not inherently affect visibility; rather, they may only create rough water conditions. Foggy conditions certainly warrant the use of navigation lights because visibility can be severely restricted, but the question asks about conditions that necessitate lights at all times, rather than just when fog is present. Therefore, the combination of overcast weather and night-time is crucial for safe navigation and necessitates the use of lights to avoid accidents.